Is dYdX really decentralized?

Could you please elaborate on the decentralization of dYdX? Given its reputation in the crypto space, it's often touted as a decentralized exchange. But what exactly makes it decentralized? How does its architecture and operations compare to traditional centralized exchanges? Also, are there any concerns or challenges related to its decentralization that investors should be aware of? It would be helpful to understand these aspects in detail to assess its credibility and suitability for trading.